Meeting Abstract
While affective information influences sensory processing, the anatomical connections between social behavior circuits and sensory regions such as the auditory system are poorly understood. Male mice (Mus musculus) interacting with females show a valence-dependent increase of serotonin (5-HT) within in the inferior colliculus (IC), an auditory midbrain structure important for processing vocalizations. However little is known about the anatomical substrates that facilitate 5-HT signaling in the IC. We used multi-fluorescence immunohistochemistry for tryptophan hydroxylase (TPH; the rate limiting enzyme in 5-HT synthesis) and the immediate early gene product Fos to test whether sub-regions of the dorsal raphe nucleus (DRN), the primary source of 5-HT to the IC, are differentially activated during sexual encounters in male mice. Additionally, we tested whether vasopressin (AVP) neurons within the bed nucleus of the stria terminalis (BNST) and paraventricular nucleus of the hypothalamus (PVN), 2 DRN afferents within the brain’s social behavior network, showed functional connectivity with DRN subcomponents. Fos immunoreactivity (-ir) within serotonergic (TPH-ir) neurons in the lateral DRN were correlated with male mounting behavior; similarly, this pattern related to female squeaks, a vocal cue associated with mounting. While there was no relationship in activity between AVP-ir neurons and lateral DRN neurons, we did find functional connectivity between BNST and other DRN subcomponents. By comparing these data with Fos-ir in IC we can start to elucidate a functional circuit-level mechanism for 5-HT release into the auditory system.
